GO:1902228 positive regulation of macrophage colony-stimulating factor signaling pathway: Signaling Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1902228 describes any process that activates or increases the frequency, rate or extent of macrophage colony-stimulating factor (M-CSF/CSF1) signaling.
• M-CSF signals through its receptor CSF1R to control macrophage survival, proliferation, differentiation and recruitment.
• Positive regulation of this pathway is essential for microglia viability in the adult brain, as CSF1R inhibition rapidly eliminates microglia.
• The pathway shapes the tumor microenvironment by driving tumor-associated macrophage infiltration and metastasis in hepatocellular carcinoma.
• M-CSF also acts on non-immune cells such as granulosa cells and osteoclast precursors, linking the pathway to reproduction and bone resorption.
• CRISPR knockout, knock-in and overexpression models enable causal dissection of positive regulators within this signaling axis.
Description
Macrophage colony-stimulating factor (M-CSF, also known as CSF1) is a cytokine that governs the survival, proliferation and differentiation of mononuclear phagocytes. The Gene Ontology term GO:1902228, positive regulation of macrophage colony-stimulating factor signaling pathway, captures any process that activates or increases the frequency, rate or extent of the signaling cascade triggered when M-CSF engages its receptor CSF1R. This term is a biological_process child of the broader regulation of M-CSF signaling and is distinct from the signaling pathway itself; it specifically annotates upstream or intracellular events that amplify the signal. Researchers study this term because M-CSF signaling is a central node in macrophage biology, and its positive regulators are candidate therapeutic targets in cancer, neurodegeneration and inflammatory disease. The pathway is perhaps best known for its role in microglia, the resident macrophages of the brain. Genetic or pharmacological blockade of CSF1R signaling in adult mice causes rapid microglia depletion, demonstrating that continuous positive regulation of M-CSF signaling is required for microglia viability. In tumors, M-CSF produced by cancer cells recruits tumor-associated macrophages that promote angiogenesis, immunosuppression and metastasis, and microRNA-148b can enhance CSF-1 signaling to drive macrophage infiltration in hepatocellular carcinoma. Beyond oncology, M-CSF signaling influences granulosa cell function in the ovary and osteoclast differentiation in bone, underscoring its broad physiological importance. Because GO:1902228 is defined by its effect on the M-CSF pathway rather than by a single molecular activity, its study requires integrating cell-based assays, phospho-signaling readouts, and genetic perturbation. This article summarizes the definition, core mechanisms, key genes, disease links and experimental methods for investigating positive regulation of M-CSF signaling, with an emphasis on CRISPR-based models that can establish causality.
positive regulation of macrophage colony-stimulating factor signaling pathway At A Glance
| GO ID | GO:1902228 |
|---|---|
| GO term | positive regulation of macrophage colony-stimulating factor signaling pathway |
| Ontology | biological_process |
| Synonym | activation of M-CSF signaling pathway; positive regulation of M-CSF signaling pathway; upregulation of macrophage colony-stimulating factor signaling pathway |
| Major function | Increases the frequency, rate or extent of M-CSF/CSF1 signaling, thereby promoting macrophage survival, proliferation, differentiation and recruitment |
| Parent term | regulation of macrophage colony-stimulating factor signaling pathway |
| Related receptor | CSF1R (CD115), the receptor tyrosine kinase for M-CSF |
| Related ligand | CSF1 (M-CSF), the primary ligand for CSF1R |
| Process context | Cell surface receptor signaling pathway; myeloid cell homeostasis |
What Is GO:1902228?
GO:1902228 is a Gene Ontology biological_process term defined as any process that activates or increases the frequency, rate or extent of macrophage colony-stimulating factor signaling pathway. In practical terms, it covers molecular events that positively regulate the cascade initiated by M-CSF binding to CSF1R, including enhanced receptor activation, increased downstream phosphorylation, or elevated expression of pathway components, but it excludes the signaling pathway itself and negative regulatory processes.
Why Is positive regulation of macrophage colony-stimulating factor signaling pathway Important in Cell Biology?
Positive regulation of M-CSF signaling is a linchpin of mononuclear phagocyte biology. Without it, macrophages and microglia cannot survive or proliferate, as shown by the rapid loss of microglia when CSF1R signaling is blocked in adult mice. In disease, excessive or sustained positive regulation of this pathway fuels tumor-associated macrophage infiltration and cancer progression, while in the brain it controls microglial homeostasis relevant to neurodegeneration. Understanding which genes and mechanisms positively regulate M-CSF signaling therefore has direct implications for cancer immunotherapy, neuroinflammation and bone disease.
• Required for microglia viability in the adult brain; CSF1R inhibition depletes microglia.
• Drives tumor-associated macrophage recruitment and hepatocellular carcinoma metastasis.
• Promotes macrophage maturation and recruitment in pituitary neuroendocrine tumors.
• Regulates osteoclast differentiation and bone resorption via PI3K-Akt-GSK3beta signaling.
• Modulates granulosa cell function in the human ovary.
• Shapes dendritic cell subsets and T cell priming in immunity.
• Contributes to myocardial ischemia/reperfusion injury by influencing macrophage polarization.
• Provides a therapeutic target for cancer, neurodegeneration and inflammatory diseases.
• Serves as a model pathway for studying receptor tyrosine kinase positive feedback and crosstalk.
• Enables CRISPR-based causal validation of candidate regulators in myeloid cells.
What Happens During positive regulation of macrophage colony-stimulating factor signaling pathway?
Ligand availability and receptor engagement
In simple terms: More M-CSF or better receptor binding means a stronger signal.
Positive regulation begins with increased availability of M-CSF (CSF1) or enhanced binding to CSF1R. In tumors, cancer cells and stromal cells secrete M-CSF, which engages CSF1R on monocytes and macrophages, thereby amplifying downstream signaling. In recurrent pituitary neuroendocrine tumors, M-CSF potentially induces recruitment and maturation of macrophages, indicating that ligand-driven positive regulation operates in human disease. In the ovary, M-CSF acts on granulosa cells, showing that positive regulation can occur in non-immune tissues.
Receptor activation and proximal phosphorylation
In simple terms: The receptor switches on and adds phosphate tags to itself and nearby proteins.
Upon M-CSF binding, CSF1R dimerizes and autophosphorylates, creating docking sites for SH2-domain proteins. Positive regulators enhance this step by increasing receptor number, stabilizing the active conformation, or reducing dephosphorylation. CSF1R signaling is necessary for microglia viability, and its positive regulation maintains the microglial population in the adult brain. In osteoclast precursors, P2X7 receptor signaling intersects with PI3K-Akt-GSK3beta to promote osteoclast differentiation, illustrating crosstalk that can amplify M-CSF responses.
Downstream kinase cascades
In simple terms: Signals travel through kinase relays to change gene expression.
Activated CSF1R recruits PI3K, GRB2/SOS and other adaptors, leading to AKT, ERK and JNK activation. Positive regulation of M-CSF signaling often involves reinforcement of these cascades. In osteoclasts, PI3K-Akt-GSK3beta signaling mediates differentiation and bone resorption downstream of M-CSF and RANKL. In dendritic cells, transcriptional programs associated with CD163+ subsets depend on CSF1R signaling, linking positive regulation to antigen presentation.
Transcriptional and functional outcomes
In simple terms: The signal changes which genes are on, altering cell behavior.
Sustained positive regulation leads to expression of macrophage lineage genes, survival factors and cytokines. M-CSF signaling promotes macrophage polarization states that influence tissue repair and injury. In myocardial ischemia/reperfusion injury, Dectin-1 regulates macrophage polarization and neutrophil infiltration, a process in which M-CSF signaling contributes to the inflammatory milieu. In hepatocellular carcinoma, microRNA-148b enhances CSF-1 signaling and tumor-associated macrophage infiltration, promoting metastasis.
Feedback and amplification loops
In simple terms: The pathway can boost itself through positive feedback.
Positive regulation can be reinforced by autocrine loops where macrophages secrete CSF1 or cytokines that further activate CSF1R. In the brain, continuous CSF1R signaling is required for microglia viability, suggesting an ongoing positive feedback that maintains the microglial niche. In tumors, macrophage-derived factors can stimulate cancer cells to produce more M-CSF, creating a feed-forward loop that sustains infiltration.
Key Genes Involved in GO:1902228 positive regulation of macrophage colony-stimulating factor signaling pathway
The following genes and proteins are central to positive regulation of M-CSF signaling, based on published functional studies.
| Gene | Major Role | Research Relevance |
|---|---|---|
| CSF1 | Ligand for CSF1R; M-CSF | Drives macrophage recruitment and maturation; target in tumors |
| CSF1R | Receptor tyrosine kinase for M-CSF | Required for microglia viability; therapeutic target |
| PIK3CA | PI3K catalytic subunit | Mediates PI3K-Akt signaling downstream of CSF1R |
| AKT1 | Serine/threonine kinase | Promotes survival and differentiation in M-CSF signaling |
| GSK3B | Glycogen synthase kinase 3 beta | Modulates osteoclast differentiation downstream of M-CSF |
| P2RX7 | P2X7 receptor | Crosstalks with PI3K-Akt-GSK3beta in osteoclasts |
| MIR148B | MicroRNA-148b | Enhances CSF-1 signaling and TAM infiltration in HCC |
| CD163 | Scavenger receptor | Marks a dendritic cell subset dependent on CSF1R signaling |
| CLEC7A | Dectin-1 | Regulates macrophage polarization in myocardial injury |
| CSF2 | GM-CSF | Related cytokine with distinct but overlapping functions |
| CD1C | Dendritic cell marker | Defines a human DC subset with CSF1R-dependent features |
| ITGAM | CD11b | Myeloid marker used to track macrophage differentiation |
| PTPRC | CD45 | Pan-leukocyte marker for macrophage identification |
| ADGRE1 | F4/80 | Mouse macrophage marker used in microglia/macrophage studies |
| P2RY12 | Microglial homeostatic marker | Lost upon CSF1R blockade, indicating microglia depletion |
| TMEM119 | Microglial marker | Used to assess microglia viability after CSF1R inhibition |
| CCL2 | Monocyte chemoattractant | Contributes to macrophage recruitment in tumors |
How Is positive regulation of macrophage colony-stimulating factor signaling pathway Regulated?
Positive regulation of M-CSF signaling is controlled at multiple levels. Ligand availability is regulated by transcriptional induction of CSF1 in cancer and stromal cells, as seen in hepatocellular carcinoma where microRNA-148b enhances CSF-1 signaling. Receptor levels and activity are modulated by internalization, degradation and phosphatases. Downstream, PI3K-Akt-GSK3beta signaling acts as a positive regulator in osteoclasts. In the brain, continuous CSF1R signaling is required for microglia viability, implying that positive regulators maintain the pathway in a constitutively active state. Crosstalk with other receptors, such as Dectin-1 in myocardial injury, can also amplify macrophage responses.
positive regulation of macrophage colony-stimulating factor signaling pathway and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| CSF1 | Hepatocellular carcinoma metastasis | CSF1 overexpression in HCC cell lines; macrophage co-culture |
| CSF1R | Microglia depletion in neurodegeneration | CSF1R knockout or inhibitor-treated mice; microglia viability assays |
| P2RX7 | Osteoclast differentiation and bone resorption | P2RX7 knockout osteoclast precursors; PI3K-Akt readouts |
| MIR148B | Tumor-associated macrophage infiltration | miR-148b mimic/inhibitor in HCC cells; TAM recruitment assays |
| CLEC7A | Myocardial ischemia/reperfusion injury | Dectin-1 knockout mice; macrophage polarization assays |
Cancer and tumor microenvironment
M-CSF signaling drives the recruitment of tumor-associated macrophages (TAMs), which promote angiogenesis, immunosuppression and metastasis. In hepatocellular carcinoma, microRNA-148b enhances CSF-1 signaling, leading to TAM infiltration and increased metastasis. M-CSF also potentially induces macrophage recruitment and maturation in recurrent pituitary neuroendocrine tumors. These findings position positive regulators of M-CSF signaling as candidate targets for cancer therapy.
Neurodegeneration and microglial homeostasis
In the adult brain, CSF1R signaling is necessary for microglia viability; inhibition rapidly eliminates microglia and unmasks a progenitor cell population. This indicates that positive regulation of M-CSF signaling is required to maintain microglia, and its dysregulation may contribute to neurodegenerative diseases characterized by microglial dysfunction.
Bone and inflammatory diseases
M-CSF is essential for osteoclast differentiation and bone resorption. P2X7 receptors and PI3K-Akt-GSK3beta signaling mediate osteoclast differentiation downstream of M-CSF, linking positive regulation to osteoporosis and inflammatory bone loss. In myocardial ischemia/reperfusion injury, Dectin-1 regulates macrophage polarization and neutrophil infiltration, processes influenced by M-CSF signaling.
Reproductive biology
M-CSF acts on human granulosa cells, suggesting a role in ovarian function and fertility. Positive regulation of M-CSF signaling in the ovary may influence folliculogenesis and luteal function, though further studies are needed.
From positive regulation of macrophage colony-stimulating factor signaling pathway-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is CSF1R required for microglia viability? | CSF1R knockout mouse or CRISPR knockout in microglial cell lines |
| Does a candidate gene positively regulate M-CSF signaling? | CRISPR knockout of candidate gene followed by phospho-CSF1R and downstream readouts |
| Does a point mutation in CSF1R alter signaling? | CRISPR knock-in of point mutation in CSF1R; compare phospho-ERK/AKT |
| Does overexpression of M-CSF drive macrophage recruitment? | CSF1 overexpression in cancer cell lines; co-culture with monocytes |
| Does a microRNA enhance CSF-1 signaling? | miR-148b overexpression or knockout in HCC cells; TAM infiltration assays |
| Does P2X7 modulate osteoclast differentiation via PI3K-Akt? | P2RX7 knockout or knock-in in osteoclast precursors; GSK3beta phosphorylation |
How to Study the positive regulation of macrophage colony-stimulating factor signaling pathway Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Western blot | Phospho-CSF1R, phospho-AKT, phospho-ERK | Quantify pathway activation after ligand stimulation |
| Flow cytometry | Surface markers (CD115, F4/80, P2RY12) | Assess macrophage differentiation and microglia viability |
| RNA-seq | Transcriptional changes | Identify downstream gene expression programs |
| CRISPR knockout screen | Gene requirement for pathway activity | Discover positive regulators of M-CSF signaling |
| Co-culture assays | Macrophage recruitment and polarization | Model tumor microenvironment interactions |
| Osteoclast differentiation assay | TRAP staining, bone resorption pits | Study M-CSF-dependent osteoclastogenesis |
| Microglia viability assay | Cell survival after CSF1R inhibition | Test positive regulators of microglia maintenance |
| miRNA mimic/inhibitor | miRNA-mediated regulation of CSF1 | Investigate post-transcriptional control |
Phospho-signaling assays
Western blotting and intracellular flow cytometry for phosphorylated CSF1R, AKT, ERK and GSK3beta are standard methods to measure positive regulation of M-CSF signaling. These assays quantify the activation state of the pathway after ligand stimulation or genetic perturbation.
Transcriptional profiling
RNA-seq and single-cell RNA-seq can identify gene expression changes downstream of M-CSF signaling, including macrophage polarization markers and cytokines. In dendritic cells, transcriptional analysis revealed a CD163+ subset dependent on CSF1R signaling. In tumors, RNA-seq of co-cultures can reveal TAM-associated signatures.
Macrophage differentiation and survival assays
Bone marrow-derived macrophage differentiation, microglia viability assays and colony-forming assays measure the functional outcomes of positive regulation. CSF1R inhibition causes rapid microglia loss, which can be quantified by flow cytometry for P2RY12 and TMEM119.
CRISPR screening and validation
Genome-wide CRISPR knockout screens can identify positive regulators of M-CSF signaling by selecting for cells that survive or proliferate under M-CSF stimulation. Hits are validated by individual knockout and phospho-signaling readouts.
How CRISPR Can Be Used to Study GO:1902228 positive regulation of macrophage colony-stimulating factor signaling pathway
Knockout
CRISPR knockout of candidate positive regulators (e.g., CSF1R, PIK3CA, AKT1) can abolish M-CSF signaling and its downstream effects. For example, CSF1R knockout or inhibition eliminates microglia in vivo, demonstrating the requirement for positive regulation. Knockout of P2RX7 impairs osteoclast differentiation, linking it to PI3K-Akt-GSK3beta signaling.
Point Mutation
CRISPR knock-in of point mutations can dissect specific phosphorylation sites or domains within CSF1R or downstream kinases. This approach can reveal gain-of-function or loss-of-function variants that alter positive regulation of M-CSF signaling, though specific mutations should be chosen based on published structural data.
Knock-in
Knock-in of reporter tags (e.g., GFP, luciferase) or epitope tags into endogenous loci allows real-time monitoring of pathway components. Tagged CSF1R knock-in can be used to track receptor trafficking and activation in live cells, facilitating studies of positive regulation.
Overexpression
CRISPR activation (CRISPRa) or lentiviral overexpression of M-CSF (CSF1) or microRNA-148b can enhance M-CSF signaling and drive macrophage recruitment. In hepatocellular carcinoma, miR-148b overexpression promotes CSF-1 signaling and TAM infiltration, providing a model for positive regulation.
How EDITGENE Supports positive regulation of macrophage colony-stimulating factor signaling pathway Research
Researchers studying positive regulation of macrophage colony-stimulating factor signaling pathway-related genes often need to determine whether a candidate gene is causally involved in pathway activation or whether it merely correlates with macrophage phenotypes. EDITGENE provides CRISPR-based cell model services to establish such causality, from knockout to knock-in and overexpression, supported by library screening and bioinformatics.
Contact EDITGENE today to design your custom CRISPR model for positive regulation of macrophage colony-stimulating factor signaling pathway research.
Frequently Asked Questions About positive regulation of macrophage colony-stimulating factor signaling pathway
What is GO:1902228?
GO:1902228 is a Gene Ontology biological_process term defined as any process that activates or increases the frequency, rate or extent of macrophage colony-stimulating factor signaling pathway.
What genes are involved in positive regulation of macrophage colony-stimulating factor signaling pathway?
Key genes include CSF1 (M-CSF), CSF1R, PIK3CA, AKT1, GSK3B, P2RX7 and MIR148B, based on published functional studies.
What is the role of CSF1R in M-CSF signaling?
CSF1R is the receptor tyrosine kinase for M-CSF; its signaling is necessary for microglia viability and macrophage survival.
How does M-CSF signaling promote cancer?
M-CSF signaling recruits tumor-associated macrophages that promote angiogenesis, immunosuppression and metastasis, as shown in hepatocellular carcinoma.
What diseases are linked to M-CSF signaling?
M-CSF signaling is linked to cancer, neurodegeneration, bone resorption disorders and myocardial injury.
How can I study positive regulation of M-CSF signaling?
Common methods include phospho-signaling assays, RNA-seq, macrophage differentiation assays and CRISPR knockout screens.
What is the difference between M-CSF and GM-CSF?
M-CSF (CSF1) and GM-CSF (CSF2) are distinct cytokines with different receptors and functions, though both regulate myeloid cells.
Does M-CSF signaling affect microglia?
Yes, CSF1R signaling is required for microglia viability; its inhibition rapidly depletes microglia in the adult brain.
Can CRISPR be used to study M-CSF signaling?
Yes, CRISPR knockout, knock-in and overexpression models are widely used to dissect positive regulators of M-CSF signaling.
What is the role of microRNA-148b in M-CSF signaling?
MicroRNA-148b enhances CSF-1 signaling and promotes tumor-associated macrophage infiltration in hepatocellular carcinoma.
Conclusion
GO:1902228, positive regulation of macrophage colony-stimulating factor signaling pathway, is a critical biological process that governs macrophage and microglia survival, proliferation and recruitment. Its dysregulation contributes to cancer progression, neurodegeneration and bone disease, making it a compelling target for therapeutic intervention. Understanding the positive regulators of this pathway requires robust experimental models, and CRISPR-based knockout, knock-in and overexpression approaches provide the causal evidence needed to move from correlation to mechanism.
References
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- 3. Fan Q et al.. 2019. Dectin-1 Contributes to Myocardial Ischemia/Reperfusion Injury by Regulating Macrophage Polarization and Neutrophil Infiltration.. Circulation 139(5):663-678 PMID: 30586706
- 4. Lu J et al.. 2024. New mechanistic understanding of osteoclast differentiation and bone resorption mediated by P2X7 receptors and PI3K-Akt-GSK3β signaling.. Cell Mol Biol Lett 29(1):100 PMID: 38977961
- 5. Matsuzaki H et al.. 2023. Macrophage colony-stimulating factor potentially induces recruitment and maturation of macrophages in recurrent pituitary neuroendocrine tumors.. Microbiol Immunol 67(2):90-98 PMID: 36461910
- 6. Xu S et al.. 2016. Role of macrophage colony-stimulating factor (M-CSF) in human granulosa cells.. Gynecol Endocrinol 32(12):1005-1008 PMID: 27791429
- 7. Ke M et al.. 2019. MicroRNA-148b-colony-stimulating factor-1 signaling-induced tumor-associated macrophage infiltration promotes hepatocellular carcinoma metastasis.. Biomed Pharmacother 120:109523 PMID: 31655310
- 8. Chen Y et al.. 2017. An epithelial-to-mesenchymal transition-inducing potential of granulocyte macrophage colony-stimulating factor in colon cancer.. Sci Rep 7(1):8265 PMID: 28811578
